Follows the efforts of Andy and Terry to meet a latest book deadline despite numerous distractions in their sophisticated tree house home, including flying cats, giant bananas, and sea monsters pretending to be mermaids.

Continuing their efforts in the ever-expanding treehouse, Andy and Terry tackle the mystery of their missing publisher, Mr. Bignose, whose disappearance has made completing their next book rather difficult.

"Andy and Terry are once again inviting readers to come hang out with them in their astonishing 39-story treehouse (it used to be 13 stories, then 26 stories, but they keep expanding). And this year they will have even more time to jump on the world's highest trampoline, toast marshmallows in an active volcano, swim in the chocolate waterfall, pet baby dinosaurs, and go head-to-trunk with the Trunkinator, since Terry has created the greatest invention...

Andy and Terry live in a 130-story treehouse. It used to be a 117-story treehouse, but they added another 13 stories. It has a soap bubble blaster, a time-wasting level, a 13-story igloo, the GRABINATOR (it can grab anything from anywhere at any time). It is a toilet paper factory, and an extraterrestrial observation center for observing aliens. As it turns out, though, it's Andy, Terry, and Jill who are being observed and then abducted by a giant...